• Preheat the oven to 350°F, and lightly grease a 2 ½-quart casserole dish.

To Make the Topping:

• In a medium bowl, combine the oats, butter, flour, brown sugar, granulated sugar, and cinnamon. Use a pastry cutter, forks, or your hands to make sure the ingredients are well mixed.. There shouldn't be any dry, sandy patches left in the bowl.
  1 cup old-fashioned rolled oats, 8 tablespoons unsalted butter, ½ cup all-purpose flour, ½ cup brown sugar, ¼ cup granulated sugar, ½ teaspoons ground cinnamon

To Make the Filling:

• Place the diced apples, lemon juice, and lemon zest into a large mixing bowl and toss to combine.
  5 medium apples, 1 large lemon
• To the bowl, add the strawberries, sugar, cornstarch, vanilla extract, and salt. Gently toss to combine the ingredients.
  4 cups fresh strawberries, ½ cup granulated sugar, ⅓ cup cornstarch, 1 teaspoon vanilla extract, ½ teaspoon salt
• Transfer the fruit mixture to the prepared dish then add with the crisp topping.
• Bake for 25-30 minutes or until the oat topping is golden brown and crunchy and the filling is bubbly.
• Let the crisp cool for 10-15 minutes before serving.
• Scroll up and see the post for tips, storage information, and FAQs.